Audio Conferencing M7017e lab 2 Team

7. Problems and Reflections
Contacts Management
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RTP and RTCP
About the network (multicast and unicast)
Protocol implementation security
router because no NAT traversal mechanism has been implemented.
We do not use RTCP but it could have been useful to get statistics about other
participants in order to adapt the quality on sender side to better match receiver’s bandwidth.
For the audio part of this, it would not be a problem to implement it in the SenderPipeline
because the streams for rooms and unicast calls are encoded separately (that is the reason
we organized it like this instead of encoding once for all channels).
Lab 2: Audioconferencing
The unicast calls make the assumption that the user is not be behind a NAT
bogus or spoofed and lead to crashes or identity thefts.
Origin and format of messages are not checked, they could be voluntarily
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The rooms rely on IP multicast to work. If it is disabled in the local network or not
properly routed (this is the cause on the open internet for example) then it will not work.
Therefore this software is particularly suitable for enterprise private networks which are fully
managed.
We thought about the possible use cases of this audioconferencing system and
discovered that it could be useful sometimes to be present in several rooms and in one
unicast conversation at the same time. However being in several unicast conversations with
different people at the same time did not seem to be useful (same effect could be achieved
by everyone joining the same room) therefore this is not supported by our software (it would
still be really easy to do it).
In summary, management of the contact list is very basic and can cause some
problems in the software. It must be used with care.
As previously, in this early stage of the software we decided to focus on the multimedia,
and for the remaining to rely on users’ goodwill and absence of malicious people on the
network.
Rooms are identified by IDs which, in fact, are directly mapped to multicast IP
addresses. Room 1 is at IP 224.1.42.1 and Room 254 at IP 224.1.42.254. For future
features, the server could associate a name to each room and probably a dynamic IP
selection algorithm and communication to clients.
Anyone can stream to a room (by knowing IP and port), without explicitly joining it in
the server. This could be mitigated by requiring the server to send to everyone in the room
the list of allowed SSRCs (unique sender identifier in RTP standard) in the room. Then
clients could simply ignore stream coming from unregistered SSRCs.
Multimedia System
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